Wireless Systems Design

Standards Update: May 2006

A monthly look at issues related to wireless standards.

1. IEEE 802.11n

This is the long awaited successor to 802.11a/b/g Wi-Fi. Using MIMO it promises greater range and reliability at rates from 100 Mbits/s to 600 Mbits/s. The split in the standards body stalled the development of this standard until a group of companies called the Enhanced Wireless Consortium got together to agree on a standard. Back in March, this was presented to the IEEE 11n Task Group and was overwhelmingly accepted as Draft 1.0. Work is proceeding now, but final ratification is not expected until July next year.

In the meantime, chip companies Airgo, Atheros, Broadcom, and Marvell have already delivered draft compliant chip versions, and equipment companies like D-Link, Linksys, and Netgear have already announced wireless router and gateway products. Apparently, the standard is close enough to a final version to allow chip and equipment manufacturers to move ahead thinking they can correct any changes later with minor firmware updates or other revisions. One critical issue is how to resolve the problem of identifying and assigning a second 20-MHz channel to boost speeds when needed.

2. IEEE 802.11s

This standard is not as well known, but progress has been good. This is the standard that defines how to implement mesh networking on a Wi-Fi system. This standard has not been as controversial as 11n, so the path to full ratification has not been as rocky. The standard applies to putting Wi-Fi access points into a mesh network to expand its range and reliability of coverage. The standard is essentially a software upgrade that will be useful primarily to large enterprise WLANs and especially to all those forthcoming municipal Wi-Fi networks that offer coverage of a city. Philadelphia, Portland, Oregon, and San Francisco are working on such systems and many other cities are considering it. The standard does not cover the meshing of individual PC, laptops, and other nodes. Ratification is expected in 2007.

For more details on IEEE standards, go to www.ieee802.org.

3. Bluetooth SIG

The Bluetooth SIG has adopted the multiband OFDM version of ultra wideband for the higher speed version of Bluetooth. See my commentary in the May 9, 2006 WSD Update newsletter and/or go to www.Bluetooth.org or www.Bluetooth.com.

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